You have recently charged 1,000 on your credit card. You can only afford to make the minimum payment of $20 per month. The interest rate on the credit card is 1.5%per month. How long will you need to pay off the $1000?

A) 2.25years

B) 5.00 years

C) 7.75 years

I know the answer is C but I don't know how to calculate it. I want the step of this question.